• Journal of Science Education
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• v.34 no.2
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• pp.432-439
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• 2010

The purpose of this study is to investigate the characteristics of the ionosphere by monitoring VLF radio wave. For this purpose, we set up the SID(Sudden Ionospheric Disturbance) monitoring station in Pohang($36.03^{\circ}N$, $129.35^{\circ}E$), Korea receiving VLF radio wave(22.2kHz) transmitted from Ebino($32.04^{\circ}N$, $130.81^{\circ}E$), Japan. The observed data of radio wave intensities are analyzed to interpret the condition of the ionosphere. We can summarize the results as follows: Radio waves show regular daily variation. We can confirm the daily variation as a result of the formation of D layer. In relation to formation or extinction of D layer, intensity of radio wave gets weak right after sunrise and sunset. Southing altitude also affects the intensity of day time radio wave. At night when D layer disappears, the radio waves shows very irregular changes. The observed radio waves also shows the influence of the seasonal ionospheric variation. Long term observation could provide more detailed interpretation of daily as well as seasonal variation of ionosphere.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.103-113
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• 2012

The ButterStar Observatory at the Dongducheon High School has been working for photographic observations of the Sun since October 16, 2002. In this study, we observed the Sun at the ButterStar observatory for 3,364 days from October 16, 2002 to December 31, 2011, and analyzed the photographic sunspot data obtained in 1,965 days. The correction factor $K_b$ for the entire observing period is 0.9519, which is calculated using the linear least square method to the relationship between the daily sunspot number, $R_B$, and the daily international relative sunspot number, $R_i$. The yearly correction factor calculated for each year varies slightly from year to year and shows a trend to change along the solar cycle. The correction factor is larger during the solar maxima and smaller during the solar minima in general. This implies that the discrepancy between a relative sunspot number, R, and the daily international relative sunspot number, $R_i$, can be reduced by using a yearly correction factor. From 2002 to 2008 in solar cycle 23, 35.4% and 64.6% of sunspot groups and 35.1% and 64.9% of isolated sunspots in average occurred in the northern hemisphere and in the southern hemisphere, respectively, and from 2008 to 2011 in solar cycle 24, 61.3% and 38.7% of sunspot groups and 65.0% and 35.0% of isolated sunspots were observed, respectively. This result shows that the occurrence frequency for each type of sunspot group changes along the solar cycle development, which can be interpreted as the emerging and decaying process of sunspot groups is different depending on the phase of solar cycle. Therefore, it is considered that a following study would contribute to the efforts to understand the dependence of the dynamo mechanism on the phase of solar cycle.

• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.293-306
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• 1999

Solar activities ejecting high energy particles influence satellites and satellite communications as well as perturb geomagnetic fields. To understand space environments near the Earth being influenced by the Sun, we must study about the magnetosphere, the ionosphere, and the atmosphere beforehand. To study this issue, we investigate some ionospheric models, atmospheric models and geomagnetic field models : IRI(International Reference Ionosphere), PIM(Parameterized Ionospheric Model) and IGRF(International Geomagnetic Reference Field). We develop the models and build a web site to serve IRI, PIM and IGRF model on the internet so that one can easily get information of daily and global ionospheric and geomagnetic variations.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.38.2-38.2
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• 2008

In Korean historical documents, there are a great number of the records for various astronomical events. In particular, historical documents of the Joseon dynasty also have the records containing observational data by an astronomical instrument. However, a quantitative analysis for the accuracy of observational values have never been studied, although there are some studies on the truth of the records themselves. Hence, we investigated observation errors during the period of the Joseon dynasty from the records of Joseon-Wang-Jo-Sil-Lok (the Annals of the Joseon Dynasty) and Seung-Jeong-Won-Il-Gi (Daily Records of the Royal Secretariat). We used the records of the Mars, supernova 1604, and Halley's Comet, and found that observational values before the Hideyoshi invasions in 1592 are relatively more accurate than those after then. However, because the number of cases used in this study is small, we think that more studies are needed to confirm our results. Nonetheless, we reckon our work will be of service to understand astronomical records of the Joseon dynasty.

• Journal of Astronomy and Space Sciences
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• v.28 no.1
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• pp.1-7
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• 2011

Characteristics of latitude variations of sunspots in the northern and southern hemispheres are investigated using the daily sunspot area and its latitude during the period from 1874 to 2009. Solar magnetic activity is portrayed in the form of sunspot, regions of concentrated fresh magnetic fields observed on the surface of the Sun. By defining center-of-latitude (COL) as an area-weighted latitude, we find that COL is not monotonically decreasing as commonly assumed. In fact, small humps (or short plateaus) between solar minima can be seen around every solar maxima. We also find that when the northern (southern) hemisphere is magnetically dominant, COL is positive (negative), except the solar cycle 23, which may give a hint that these two phenomena are consistently regulated by one single mechanism. As a result of periodicity analysis, we find that several significant periodicities, such as, of ~5.5, ~11, ~49, and ~167 years.

• Journal of the Korean housing association
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• v.3 no.1
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• pp.47-56
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• 1992

This study attempts to fiugure out how residents differentially perceive the storage according to the housing types and sizes. The major findings are as follows: 1) The residents in the tenement house dissatisfy the storage space more than those in the detached house. 2) It is the arrangement that is considered as the most important factor while storaging. 3) It is non-daily goods that is the most difficult item to store. 4) Most information about storage is obtained form mass media.

• Journal of Astronomy and Space Sciences
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• v.17 no.2
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• pp.233-240
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• 2000

Five scientific instruments are planned on KAISTSAT-4 that is scheduled to be launched in 2002. A far ultra-violet imaging spectrograph and a set of space plasma instruments are currently being designed. The imaging spectrograph will make observations of astronomical objects and Earth's upper atmosphere. The plasma instrumentation is capable of fast measuring the thermal magnetosphere plasmas, cold ionospheric plasmas and the Earth's magnetic fields. Major system drivers and constraints on the payloads as well as the spacecraft are identified. A preliminary analysis of the K-4 mission has been undertaken with the system requirements that are derived from the system drivers. Detailed investigation shows that Sun-synchronous orbits with approximate altitudes of 800km are optimal to satisfy the identified requirements. Comparisons with other orbits of different inclinations are also shown. Four operation modes and a daily schedule of spacecraft maneuver are found from the Sun-synchronous orbital model. It is shown that the scientific objectives of K-4 can be achieved with moderate levels of design and operation risks.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2005.11a
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• pp.115-119
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• 2005

This study is to examine changes since autonomy of lotting-out price of apartment house and planning factors related to sale of apartment house through leaflet of sale of apartment house. Objects of the study were leaflets of sale of apartment houses through the Donga Il Bo daily newspaper from 2001 to 2003. The results of research can be summarized to three. First, traffic of locational factors in advertisement of sale of apartment house showed the highest frequency and it was found that it was an important planning factor of apartment house. Second, considering that advanced facilities and the highest finishing materials were used, quality of apartment house has been advanced. Third, considering that community space, theme park and green zone showed high occupancy in external space, there has been high increase in external space as well as in internal one since autonomy of lotting-out price.

• Journal of East-Asian Urban History
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• v.2 no.1
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• pp.27-63
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• 2020

The emergence of coffee shops and other public spaces in modern Shanghai shows the appearance of the "mass" centered on the middle class. Furthermore, we can further explore the different development paths of the publicity of modern Chinese urban society. The emergence of new public leisure spaces, such as cafes, provides a model of modern life style and a stage of daily publicity for the middle class in Shanghai. With the convenience provided by this kind of public space, people are able to clean up their old opinions and be better at accepting new ideas. A more sensitive and flexible public opinion of Enlightenment has gradually formed in urban life.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4184-4190
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• 2014

The present paper examined the stress and ADL (activities of daily living) index in relation to the characteristics of the elderly in nursing homes. For this study, questionnaires were given to 110 seniors in the N-district of Seoul, and S-myeon, Hoengseong-gun, Gangwon Province from May 1 to September 30, 2013. For data analysis, t-test, correlation analysis, and multiple regression analysis were performed using the SPSSWIN18.0 program. The analysis of actual proof was made at a significance level of 5 percent. The findings from the analyses were as follows: first, the relocation syndrome into nursing homes has a positive correlation with the stress of deficient family visits in the category of daily stresses; second, depression has a positive correlation with the stresses of deficient private time and space and deficient family visits in the category of daily stresses; third, weight control has a positive correlation only with the stress of deficient private time and space in the category of daily stresses, whereas a nutrition deficiency has positive correlation with the stress of deficient family visits in the category of daily stresses. These findings may serve as ground source data for establishing policies regarding the stresses in relation to the characteristics and ADL index of the elderly in nursing homes.